The art of taming light: ultra-slow and stopped light

Phys Rev a, 2003

The optical response of a moving medium suitably driven into a slow-light propagation regime strongly depends on its velocity. This effect can be used to devise a novel scheme for imaging ultraslow velocity fields. The scheme turns out to be particularly amenable to study in-situ the dynamics of collective and topological excitations of a trapped Bose-Einstein condensate. We illustrate the advantages of using slow-light imaging specifically for sloshing oscillations and bent vortices in a stirred condensate.

We study propagation of short laser pulses in a Bose-Einstein condensate taking into account dispersive effects under the conditions for electromagnetically induced transparency. We calculate dispersion coefficients using typical experimental parameters of slow-light schemes in condensates. By numerically propagating the laser pulse, and referring to theoretical estimations, we determine the conditions for which dispersion starts to introduce distortions on the pulse shape.

2018

We investigate lensing and waveguiding properties of an atomic BoseEinstein condensate for ultraslow pulse generated by electromagnetically induced transparency method. We show that a significant time delay can be controllably introduced between the lensed and guided components of the ultraslow pulse. In addition, we present how the number of guided modes supported by the condensate and the focal length can be controlled by the trap parameters or temperature.

We investigate potential of atomic Bose-Einstein condensates as dynamic memory devices for coherent optical information processing. Specifically, the number of ultra-slow pulses that can be simultaneously present within the storage time in the condensate has been analyzed. By modelling short pulse propagation through the condensate, taking into account high-order dispersive properties, constraints on the information storage capacity have been discussed. The roles of temperature, spatial inhomogeneity, the interatomic interactions and the coupling laser on the pulse shape have been pointed out. For a restricted set of parameters, it has been found that coherent optical information storage capacity would be optimized.

2007

We investigate potential of atomic Bose-Einstein condensates as dynamic memory devices for coherent optical information processing. Specifically, the number of ultra-slow pulses that can be simultaneously present within the storage time in the condensate has been analyzed. By modelling short pulse propagation through the condensate, taking into account high-order dispersive properties, constraints on the information storage capacity have been discussed. The roles of temperature, spatial inhomogeneity, the interatomic interactions and the coupling laser on the pulse shape have been pointed out. For a restricted set of parameters, it has been found that coherent optical information storage capacity would be optimized.

One-dimensional propagation of ultraslow optical pulses in an atomic Bose-Einstein condensate taking into account the dispersion and the spatial inhomogeneity is investigated. Analytical and semi-analytical solutions of the dispersive inhomogeneous wave equation modeling the ultraslow pulse propagation are developed and compared against the standard wave equation solvers based upon Cranck-Nicholson and pseudo-spectral methods. The role of curvature of the trapping potential of the condensate on the amount of dispersion of the ultraslow pulse is pointed out.

Journal of Physics: Condensed Matter, 2004

Slow and superluminal group velocities can be observed in any material that has large normal or anomalous dispersion. While this fact has been known for more than a century, recent experiments have shown that the dispersion can be very large without dramatically deforming a pulse. As a result, the significance and nature of pulse velocity is being reevaluated. In this review, we discuss some of the current techniques used for generating ultra-slow, superluminal, and even stopped light. While ultra-slow and superluminal group velocities have been observed in complicated systems, from an applications point of view it is highly desirable to do have this done in a solid that can operate at room temperature. We describe how coherent population oscillations can produce ultra-slow and superluminal light under these conditions. Contents

Physical Review A, 2005

We study the dispersion and absorption spectra of a weak probe in a ⌳-type three-level atomic system with closely ground sublevels driven by a strong field and damped by a broadband squeezed vacuum. We analyze the interplay between the spontaneous generated coherence and the squeezed field on the susceptibility of the atomic system. We find that by varying the intensity of the squeezed field the group velocity of a weak pulse can change from subluminal to superluminal. In addition we exploit the fact that the properties of the atomic medium can be dramatically modified by controlling the relative phase between the driving field and the squeezed field, allowing us to manipulate the group velocity at which light propagates. The physical origin of this phenomenon corresponds to a transfer of the atomic coherence from electromagnetically induced transparency to electromagnetically induced absorption. Besides, this phenomenon is achieved under nearly transparency conditions and with negligible distortion of the propagation pulse.

Proceedings of SPIE, 2007

Light can be slowed down to ultraslow speeds v ia electromagnetically induced transparency in atomic Bose-Einstein condensates. This is thought to be useful for storage of quantum information for weak probe pulses. We investigate the effects of inhomogeneous density profile of the condensate on propagation of such ultraslow pulses. We find that spatial density of an atomic condensate leads to a graded refractive index profile, for an off-resonant probe pulse when condensate parameters are suitably chosen. Within the window of negligible absorption, conditions for degenerate multiple waveguide modes are determined. Both analytical and numerical studies are presented to reveal the effects of experimentally controllable parameters, such as temperature and interatomic interaction strength on the number of modes. Group velocity dispersion and modal dispersion are discussed. The effect of waveguide dispersion, in addition to usual material dispersion, on ultraslow pulses is pointed out.

2009

One dimensional propagation of ultraslow optical pulses in an atomic Bose-Einstein condensate taking into account the dispersion and the spatial inhomogeneity is investigated. Analytical and semi-analytical solutions of the dispersive inhomogeneous wave equation modeling the ultraslow pulse propagation are developed and compared against the standard wave equation solvers based upon Cranck-Nicholson and pseudo-spectral methods. The role of curvature of the trapping potential of the condensate on the amount of dispersion of the ultraslow pulse is pointed out.